Cub Cadet Lawn Tractor will not restart

I'm not familiar with your mower (a) because it's probably too new compared to those I'm familiar with and (b) you haven't identified it besides saying it's a Cub Cadet. The next thing to check is whatever chokes or primes that engine. Some engines have a choke lever; others have an automatic choke; yet others have a primer bulb. Whatever it is that yours employs, check that it's working.
 
There are certainly other things that would make an engine hard to start, but since you mentioned that it's only a year old, I wouldn't yet pay attention to things like low compression or valve clearance. First rule out malfunction in the choke or prime, as your case may be.